BLOCK 31 (DEVONIAN), District 08, Texas

A field is the Railroad Commission's unit of geology and of regulation. Its spacing rule is what decides how many wells an acreage can hold.

Leases
76
with a page here
Operators
14
Value, all time
$3.71 bn
87% of the register's 87
Discovered
1945-10-27
Oil and gas

Our estimate: volumes the operator filed with the Commission, valued at the EIA first-purchase price for that month. It is not a payment anyone received, and it is not a royalty. It sums the 76 leases in this field that have a page here — 87% of the register's 87 — so it understates the field.

Production, 2025

The Railroad Commission's Oil and Gas Annual Report for 2025, its most recent. These are the state's figures for the whole field, not ours.

WellsIn the fieldProducingProduced in 2025Also producedCumulative
Oil21511994,467 bbl4,121,214 mcfcasinghead232,344,107 bblsince discovery
Gas44412,606,073 mcf12,882 bblcondensate60,429,885 mcfsince 1970

The discovery well's oil measured 41.3° API gravity, perforated at 8,812 ft.

Hydrogen sulphide

Spacing rule

What the Commission requires of a well on this field.

WellsRuleEffectiveFrom the lease lineBetween wellsAcres per unitMax diagonal
GasB1988-12-02467 ft800 ft803,250 ft
GasO1988-12-02467 ft800 ft402,100 ft
GasO1988-12-02467 ft800 ft201,500 ft
OilB1988-12-12467 ft800 ft803,250 ft
OilO1988-12-12467 ft800 ft402,100 ft
OilO1988-12-12467 ft800 ft201,500 ft

Commission remarks: FORMULA IS SUSPENDED AND ALL OVERPRODUCTION IS CANCELLED.

County

Leases in this field

Every lease here files this field's number with the Commission and has a page on this site.

LeaseOperatorValue
BLOCK 31 UNITOXY USA EOR, LLC$3.29 bn
UNIVERSITY -42-FORMENTERA OPERATIONS LLC$32.1 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$29.6 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$27.2 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$22.6 M
UNIVERSITY #1SCOUT ENERGY MANAGEMENT LLC$19.8 M
UNIVERSITY DEVONIAN A 37FORMENTERA OPERATIONS LLC$18.4 M
UNIVERSITY O 25FORMENTERA OPERATIONS LLC$16.9 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$16.5 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$14.4 M
UNIVERSITY -A-SCOUT ENERGY MANAGEMENT LLC$14.3 M
UNIVERSITY 48FORMENTERA OPERATIONS LLC$12.3 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$11.1 M
UNIVERSITY 25AFORMENTERA OPERATIONS LLC$10.6 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$9.6 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$8.8 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$8.6 M
UNIVERSITY -36A-FORMENTERA OPERATIONS LLC$8.4 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$8.4 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$8.0 M
STATE -LB-SCOUT ENERGY MANAGEMENT LLC$7.1 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$6.9 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$6.6 M
UNIVERSITY -36B-FORMENTERA OPERATIONS LLC$5.1 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$4.8 M
UNIVERSITY "C"WALSH & WATTS, INC.$4.8 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$4.4 M
ATLANTIC UNIVERSITYFORMENTERA OPERATIONS LLC$4.0 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$4.0 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$3.7 M
UNIVERSITYWALSH & WATTS, INC.$3.4 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$3.3 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$3.0 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$3.0 M
UNIVERSITY -H-SCOUT ENERGY MANAGEMENT LLC$3.0 M
UNIVERSITYBAKER OPERATING, INC.$2.8 M
UNIVERSITY "B"WALSH & WATTS, INC.$2.7 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$2.5 M
UNIVERSITY -A-WALSH & WATTS, INC.$2.5 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$2.4 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$2.3 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$2.2 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$2.1 M
UNIVERSITY 35FORMENTERA OPERATIONS LLC$2.0 M
UNIVERSITY 35AFORMENTERA OPERATIONS LLC$1.7 M
UNIVERSITY 38 -A-APACHE CORPORATION$1.7 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$1.6 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$1.5 M
BLOCK 31 UNITOXY USA EOR, LLC$1.4 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$1.4 M
UNIVERSITY 38BSLANT OPERATING, LLC$1.2 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$1.2 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$1.1 M
BLOCK 31 UNITOXY USA INC.$1.0 M
BLOCK 31 UNITHILCORP ENERGY COMPANY$972 k
UNIVERSITY 38FORMENTERA OPERATIONS LLC$933 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$865 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$836 k
UNIVERSITY -U-BP AMERICA PRODUCTION COMPANY$835 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$806 k
KING 29FORMENTERA OPERATIONS LLC$757 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$620 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$601 k
UNIVERSITY -35-FORMENTERA OPERATIONS LLC$576 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$550 k
UNIVERSITY 38 -A-SLANT OPERATING, LLC$543 k
UNIVERSITY -38-BP AMERICA PRODUCTION COMPANY$536 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$516 k
UNIVERSITY -U-WTG EXPLORATION$496 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$424 k
BLOCK 31 UNITHILCORP ENERGY COMPANY$260 k
UNIVERSITY -C-MERIT ENERGY COMPANY$111 k
UNIVERSITY 44FORMENTERA OPERATIONS LLC$60 k
BLOCK 31 UNITOXY USA INC.$52 k
UNIVERSITY -3031-20TH CENTURY PIPE & EQUIP.CO.INC$49 k
UNIVERSITY -37-ARCO OIL & GAS CO.$3 k

Field number 09358450, from the Railroad Commission's field register. The register's own index resolves 87 leases and 441 wells to this field by name, over every lease in Texas rather than only those with a page here. It resolves a lease by NAME and refuses an ambiguous one, so it counts nothing for a field that shares its name with another — which is why the lease count above comes from the field number instead.